自定义控件中使用动画

package de.bvb.widget;

import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.AnticipateInterpolator;

/**
 *  自定义控件 动画
 */
public class RecView extends View {

    private Paint paint;
    private int measuredHeight;
    private int measuredWidth;
    private ValueAnimator valueAnimator;

    public RecView(Context context) {
        this(context, null);
    }

    public RecView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public RecView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        paint = new Paint();
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.parseColor("#ff0000"));
        valueAnimator = ValueAnimator.ofFloat(0, 0);
    }

    float scale;

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        measuredHeight = getMeasuredHeight();
        measuredWidth = getMeasuredWidth();
    }

    @Override
    protected void onDraw(final Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawRect(0, 0, scale * measuredWidth, measuredHeight, paint);
    }

    /**
     * 页面调用事件
     * @param scale 填充的进度
     * @param hasAnimator 是否使用动画
     */
    public void setScale(float scale, boolean hasAnimator) {
        this.scale = scale;
        if (!hasAnimator) {
            invalidate();
        } else if (hasAnimator && !valueAnimator.isRunning()) {
            startAnimator();
        }
    }

    private void startAnimator() {
        valueAnimator = ValueAnimator.ofFloat(0, scale);
        valueAnimator.setDuration(5000);
        valueAnimator.setInterpolator(new AnticipateInterpolator());
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                RecView.this.scale = Float.parseFloat(animation.getAnimatedValue().toString());
                invalidate();
            }
        });
        valueAnimator.start();
    }
}